Mojo C++ bindings: assume that all imported mojoms have the same variant as current mojom

mojo/public/tools/bindings/generators/cpp_templates/module.h.tmpl

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 {%- if variant -%}
 {%-   set variant_path = "%s-%s"|format(module.path, variant) -%}
 {%- else -%}
 {%-   set variant_path = module.path -%}
 {%- endif -%}
 
@@ skipping 17 matching lines @@
 #include "mojo/public/cpp/bindings/lib/control_message_handler.h"
 #include "mojo/public/cpp/bindings/lib/control_message_proxy.h"
 #include "mojo/public/cpp/bindings/lib/serialization.h"
 #include "mojo/public/cpp/bindings/map.h"
 #include "mojo/public/cpp/bindings/message_filter.h"
 #include "mojo/public/cpp/bindings/no_interface.h"
 #include "mojo/public/cpp/bindings/struct_ptr.h"
 #include "mojo/public/cpp/bindings/struct_traits.h"
 #include "{{variant_path}}-internal.h"
 {%- for import in imports %}
+{%-   if variant %}
+#include "{{"%s-%s.h"|format(import.module.path, variant)}}"
+{%-   else %}
 #include "{{import.module.path}}.h"
+{%-   endif %}
 {%- endfor %}
 {%- if not for_blink %}
 #include "mojo/public/cpp/bindings/array.h"
 #include "mojo/public/cpp/bindings/string.h"
 {%- else %}
 #include "mojo/public/cpp/bindings/wtf_array.h"
 #include "third_party/WebKit/Source/wtf/text/WTFString.h"
 {%- endif %}
 
 {%- for namespace in namespaces_as_array %}
@@ skipping 136 matching lines @@
 {%- endfor %}
 
 {%- if variant %}
 }  // namespace {{variant}}
 {%- endif %}
 {%- for namespace in namespaces_as_array|reverse %}
 }  // namespace {{namespace}}
 {%- endfor %}
 
 #endif  // {{header_guard}}